CN101690409A - Discharge lamp operating device, illumination device, and liquid crystal display device - Google Patents
Discharge lamp operating device, illumination device, and liquid crystal display device Download PDFInfo
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- CN101690409A CN101690409A CN200880019381.0A CN200880019381A CN101690409A CN 101690409 A CN101690409 A CN 101690409A CN 200880019381 A CN200880019381 A CN 200880019381A CN 101690409 A CN101690409 A CN 101690409A
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- 239000004973 liquid crystal related substance Substances 0.000 title claims abstract description 21
- 238000005286 illumination Methods 0.000 title abstract description 3
- 238000001514 detection method Methods 0.000 claims abstract description 25
- 239000003990 capacitor Substances 0.000 abstract description 42
- 238000004804 winding Methods 0.000 abstract 1
- 238000010586 diagram Methods 0.000 description 11
- 230000005856 abnormality Effects 0.000 description 8
- 238000009499 grossing Methods 0.000 description 6
- 230000000087 stabilizing effect Effects 0.000 description 5
- 230000010355 oscillation Effects 0.000 description 4
- 238000009413 insulation Methods 0.000 description 3
- 239000012467 final product Substances 0.000 description 2
- 230000003071 parasitic effect Effects 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005669 field effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
- H05B41/14—Circuit arrangements
- H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
- H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
- H05B41/295—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices and specially adapted for lamps with preheating electrodes, e.g. for fluorescent lamps
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
- H05B41/14—Circuit arrangements
- H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
- H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
- H05B41/295—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices and specially adapted for lamps with preheating electrodes, e.g. for fluorescent lamps
- H05B41/298—Arrangements for protecting lamps or circuits against abnormal operating conditions
- H05B41/2981—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions
- H05B41/2985—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the circuit against abnormal operating conditions against abnormal lamp operating conditions
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S315/00—Electric lamp and discharge devices: systems
- Y10S315/04—Dimming circuit for fluorescent lamps
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- Circuit Arrangements For Discharge Lamps (AREA)
Abstract
The invention provides a discharge lamp operating device, an illumination device, and a liquid crystal display device. A series circuit having a diode (D1) and a resistor (R1) is connected in parallelto a filament (FL1). A series circuit having a diode (D2) and a resistor (R2) is connected in parallel to a filament (FL2). The filaments (FL1, FL2) are preheated by a preheat current supplied via preheat capacitors (C4, C5) from secondary windings (T22-1, T22-2) of a preheat transformer (T2). Detection circuits (11, 12) detect DC voltage components of the preheat capacitors (C4, C5). Comparators(13, 14) compare DC voltage components of the preheat capacitors (C4, C5) to a reference voltage.Upon detection of an error in the filaments (FL1, FL2), the comparators (13, 14) make a control circuit (15) protect an inverter circuit.
Description
Technical field
The present invention relates to a kind of discharge lamp with filament (filament) be carried out lighting apparatus for discharge lamp, the lighting device that uses this lighting apparatus for discharge lamp and the liquid crystal indicator that high frequency is lighted.
Background technology
In recent years, in lighting devices such as liquid crystal indicators such as PC, OA equipment (office automation device), LCD TV and billboard lamp, use more the light source that illuminates display surface from the back side (backlight, backlight).Wherein, have a kind ofly as everyone knows, and possess a plurality of discharge lamps of being disposed on the reflecting plate and be disposed at the direct-type backlight (direct backlight) of the diffuser plate (diffuser plate) of the top of discharge lamp for high brightness ground illuminates the light-emitting area of broad.
In the field of liquid crystal indicator, require picture maximization, high brightnessization and homogenizing.Therefore, exist the quantity of the discharge lamp that is adopted in each group (set) device to increase, the tube voltage of employed discharge lamp (tube voltage) becomes more high-tension tendency.For example, in 32 inches sizes of CCFL (Cold Cathode Fluorescent Lamp, cold-cathode fluorescence lamp) backlight, tube voltage is about 1kVrms.Therefore, can't ignore the influence of the parasitic capacitance between high impedance load and the basket, the Luminance Distribution that can occur discharge lamp under the influence of the electric current that leaks to basket produces deviation, has the problem of brightness irregularities.
To this, consider to utilize the high and low hot-cathode fluorescent lamp (HCFL:Hot CathodeFluorescent Lamp) of tube voltage than CCFL output.If use HCFL, then compare the number of discharge lamp is fallen sharply, and can reduce lighting circuit with CCFL.And leakage current low because of tube voltage, the parasitic capacitance between discharge lamp and the basket of flowing through diminishes, so the deviation of the brightness of discharge lamp also can diminish.In addition, because of noise is low, so the influence of peripheral circuit is also reduced.
Yet, utilizing change-over circuit HCFL to be carried out in the lighting apparatus for discharge lamp that high frequency lights, at no-load condition (state that discharge lamp has come off) or end of lifetime etc., when the filament of discharge lamp breaks, if proceed the vibration of change-over circuit, then efferent and receptacle portion branch produce high voltage, thereby have danger such as electric shock takes place.Therefore, when above-mentioned abnormal conditions have taken place, generally forcibly stop the vibration of change-over circuit.
In No. the 3858317th, the Japanese patent gazette (below be called " patent documentation 1 ") following structure is disclosed: for a pair of filament to discharge lamp carries out preheating, be connected resonant capacitance (capacitor C 1) between the non-power supply side terminal of the non-power supply side terminal of a filament and another filament therein, voltage between the stem stem (stem) of detection discharge lamp, when this detected voltage surpasses the designated value of expression filament broken string, stop the output of change-over circuit or reduction change-over circuit.
Yet, shown in patent documentation 1, be that preheating is used in the lighting apparatus for discharge lamp of electric capacity with the resonant capacitance double as, the electric current of filament is determined by resonance characteristic.But, be heated the characteristic that its resistance value can increase if filament has.Therefore, when filament was flow through in constant current, voltage can increase according to resistance value, even filament is normal, the voltage between stem stem also bigger change can occur.Thereby, be used to detect the detection threshold of the comparator of the voltage between stem stem, must be set at the mobility scale of the voltage between the stem stem that exceeds under the normal condition.Thus, in the lighting apparatus for discharge lamp of patent documentation 1, there is the low problem of accuracy of detection of the broken string of filament.
When with use for discharge lamp during in liquid crystal display television by using backlight, because of requiring slimming backlight, so there is the tendency of tubuleization more in discharge lamp.In addition, have the long-life, so the preheating condition of filament is subjected to strict restriction because of the LCD TV requirement is backlight.Therefore, comparatively it is desirable to adopt can with the resonance characteristic of the lighting apparatus for discharge lamp lighting apparatus for discharge lamp of the preheat curent of regulation filament independently.
To this, the open communique spy of Japan Patent opens in flat 10-284275 number (below be called " patent documentation 2 ") and discloses a kind of lighting apparatus for discharge lamp, using preheating transformer that preheat curent is flow in the lighting apparatus for discharge lamp of coil preheating method of filament, make the direct current filament of discharge lamp of flowing through, and detect the broken string of filament according to having or not of this direct current.In this lighting apparatus for discharge lamp, can stipulate preheat curent independently with resonance characteristic, but according to the resistance value of filament, the preheat curent of filament can change, thereby the change in voltage between stem stem is little.
Yet, in the lighting apparatus for discharge lamp shown in the patent documentation 2,, between DC power supply portion and filament, be connected with resistance in order to make the direct current filament of flowing through.At this moment, if consider the stress (stress) of the starting resistor etc. of discharge lamp, the problem that the parts number increases takes place in a plurality of resistance that then need to connect.
And, at needs during, must be provided for detecting the power supply unit of the broken string of filament in addition with described DC power supply portion and discharge lamp load insulation, the problem that the parts number increases takes place equally.
The object of the present invention is to provide a kind of parts number that need not to increase, just can detect the lighting apparatus for discharge lamp of the broken string of filament, the lighting device that possesses this lighting apparatus for discharge lamp and liquid crystal indicator safely.
Summary of the invention
Lighting apparatus for discharge lamp provided by the present invention is lighted the discharge lamp with filament, comprising: will be converted to high frequency output from the output of DC power supply portion, and be supplied to the change-over circuit of described discharge lamp; Comprise and be used for to the pre-heat coil of described filament supply preheat curent and the filament preheating circuit that is connected in the preheating usefulness electric capacity between described pre-heat coil and the described filament; Comprise the rectifier cell and the resistance that are connected in series, and be connected in parallel in the series circuit of described filament; Detect the testing circuit of described preheating with the direct voltage composition of electric capacity; The comparator that the output and the reference voltage of described testing circuit compared; And the output that receives described comparator, limit the output of described change-over circuit or stop the control circuit of the action of described change-over circuit.
And lighting device provided by the present invention comprises above-mentioned lighting apparatus for discharge lamp.
And liquid crystal indicator provided by the present invention comprises above-mentioned lighting apparatus for discharge lamp.
Description of drawings
Fig. 1 is the circuit diagram of the lighting apparatus for discharge lamp of embodiments of the invention 1.
Fig. 2 is the action specification figure of lighting apparatus for discharge lamp shown in Figure 1.
Fig. 3 represents to use with respect to the preheating of the variation of the resistance value of filament the variation of the direct voltage composition of electric capacity.
Fig. 4 represents the circuit diagram of employed testing circuit and comparator in the lighting apparatus for discharge lamp shown in Figure 1.
Fig. 5 represents the circuit diagram of the lighting apparatus for discharge lamp of embodiments of the invention 2.
Fig. 6 represents the circuit diagram of the testing circuit in the lighting apparatus for discharge lamp of embodiments of the invention 3.
Fig. 7 represents the circuit diagram of the lighting apparatus for discharge lamp of embodiments of the invention 4.
Fig. 8 is the action specification figure of lighting apparatus for discharge lamp shown in Figure 7.
Fig. 9 represents the structure chart of the liquid crystal indicator of embodiments of the present invention.
Embodiment
(embodiment 1)
Fig. 1 is the circuit diagram of the lighting apparatus for discharge lamp of embodiments of the invention 1.The DC of DC power supply portion is made of the power circuit of direct voltage of output appointment, for example comprises commercial ac voltage is carried out the rectification circuit of full-wave rectification and the commercial ac voltage through full-wave rectification is boosted and the boost chopper (boost choppercircuit) of smoothing (smooth).
The negative pole of the DC of DC power supply portion is connected in primary side reference potential G1 (ground connection).Between the positive pole and negative pole of the DC of DC power supply portion, be connected with by the switch element Q1 that is connected in series, half-bridge circuit (halfbridge circuit) that Q2 constitutes.Switch element Q1, Q2 are for example by power MOSFET (Metal Oxide Semiconductor Field EffectTransistor, mos field effect transistor) constitutes, receive output via driver 16 from control circuit 15, and with high frequency hocket conducting, disconnection.The primary coil T11 that is connected with insulating transformer T1 with electric capacity C8 is blocked at the two ends of switch element Q2 via direct current.
In addition, switch element Q1, Q2, direct current block with electric capacity C8 and insulating transformer T1 and constitute change-over circuit (inverter circuit) I1.Change-over circuit I1 will be converted to high frequency output from the output of the DC of DC power supply portion, and be supplied to discharge lamp FL.
Be connected in parallel to the series circuit of the primary coil T21 of capacitor C 3 and preheating transformer T2 at the secondary coil T12 of insulating transformer T1.Preheating transformer T2 comprise the output that receives change-over circuit I1 primary coil T21 and with the magnetic-coupled a pair of secondary coil T22-1 of primary coil T21, T22-2.Secondary coil T22-1 is connected in filament FL1 via preheating with electric capacity C4.Secondary coil T22-2 is connected in filament FL2 via preheating with electric capacity C5.
Discharge lamp FL is the hot cathode type fluorescent lamp (hot cathode type fluorescentlamp) with filament FL1, FL2.Constitute filament preheating circuit by capacitor C 3, preheating with electric capacity C4, C5 and preheating transformer T2.
Secondary coil T12 at insulating transformer T1 is connected with resonant circuit I2.Resonant circuit I2 comprises inductor L1, reaches capacitor C 1, C2.Be connected with discharge lamp FL at resonant circuit I2, will be supplied to discharge lamp FL from the high frequency output of change-over circuit I1 output.The capacitor C 2 of resonant circuit I2 is connected between the terminal A of inductor L1 and filament FL1.The capacitor C 1 of resonant circuit I2 is connected between the terminal C and inductor L1 of filament FL2.
Terminal B is connected in secondary coil T22-1 via preheating with electric capacity C4.And terminal D is connected in secondary coil T22-2 via preheating with electric capacity C5.
Be connected in parallel to the series circuit of diode D1 (example of rectifier cell) and resistance R 1 between the terminal A of filament FL1 and the terminal B.The anode of diode D1 (anode) is connected in capacitor C 2, and negative electrode (cathode) is connected in resistance R 1.
And, be connected in parallel to the series circuit of diode D2 and resistance R 2 between the terminal C of filament FL2 and the terminal D.The anode of diode D2 is connected in insulating transformer T1, and negative electrode is connected in resistance R 2.
At this, the current potential of terminal C is made as primary side reference potential G2, be that benchmark is referred to as high-pressure side, low-pressure side with the accurate current potential G2 of secondary side group.Therefore, filament FL1 becomes on high-tension side filament, and filament FL2 becomes the filament of low-pressure side.Primary side reference potential G2 is by insulating transformer T1 and primary side reference potential G1 insulation.
Testing circuit 11 is connected in parallel in preheating electric capacity C4, detects the direct voltage composition of preheating with electric capacity C4.Thus, detect the broken string of filament FL1.Testing circuit 12 is connected in parallel in preheating electric capacity C5, detects the direct voltage composition of preheating with electric capacity C5.Thus, detect the broken string of filament FL2.
Charging to preheating is that direction by diode D1, D2 is determined with the polarity of the direct voltage of electric capacity C4, C5.Even if under filament FL1, the FL2 situation that any terminal from terminal A to D has come off, preheating also is recharged with identical polarity with electric capacity C4, C5.In addition, testing circuit 11,12 is as long as consider that charging to preheating constitutes with the polarity of the direct voltage composition of electric capacity C4, C5, so the direction of diode D1, D2 is not particularly limited.
But, in order to suppress the magnetic bias of preheating transformer T2, as shown in Figure 1, the direction that comparatively it is desirable to make diode D1, D2 polarity each other disposes on the contrary, makes that one of them polarity of preheating transformer T2 output is that forward, another polarity of diode D1 is the forward of diode D2.Just, in this lighting apparatus for discharge lamp, the output of preheating transformer T2 is the DC power supply that the burn out detection of filament FL1, FL2 is used by double as, when the resistance of equal value (equivalent resistance) of filament FL1, FL2 when increasing, via diode D1, D2 and resistance R 1, R2, preheating is carried out charging with electric capacity C4, C5 from preheating transformer T2.
Fig. 2 is the action specification figure of lighting apparatus for discharge lamp shown in Figure 1.At this, the action during on high-tension side filament FL1 broken string describes, and the action during the filament FL2 of low-pressure side broken string is also substantially the same.Arrow among the figure is represented flowing of direct current.
If the resistance of equal value of filament FL1 is Rf1.Resistance R _ f of equal value 1 just often and the relation of resistance R 1 be made as Rf1＜＜R1.With the direct current of electric capacity C4 preheating is charged with electric capacity C4 via the preheating of flowing through of diode D1, resistance R 1 even if utilize from preheating transformer T2, when the polarity inversion of the output of preheating transformer T2, preheating also can be discharged via filament with the charging charge of electric capacity C4.So preheating is used hardly can the remnant DC voltages composition among the electric capacity C4.Therefore, preheating just often is roughly 0 with the direct voltage composition of electric capacity C4.
Now, suppose filament FL1 broken string, the resistance R _ f of equal value 1 of filament FL1 increases.Below, the terminal that the broken string of filament FL1 comprises cut-out, the filament FL1 of filament FL1 comes off and the situations such as loose contact of terminal A to D.Like this, utilization is charged with electric capacity C4 to preheating with the direct current of electric capacity C4 via the preheating of flowing through of diode D1, resistance R 1 from preheating transformer T2, when the polarity inversion of preheating transformer T2, preheating then can be via filament FL1 discharge with the charging charge of electric capacity C4, perhaps is difficult to discharge with just often comparing to become.Consequently preheating is with producing the direct voltage composition among the electric capacity C4.By detecting the broken string that this direct voltage composition can detect filament FL1.
Fig. 3 represents to use with respect to the preheating of the variation of the resistance value of filament the variation of the direct voltage composition of electric capacity.Transverse axis is represented the resistance R _ f of equal value 1 of filament FL1, and the longitudinal axis is represented the direct voltage composition of preheating with electric capacity C4.The direct voltage composition rises for beginning near the R1/10 from resistance R _ f 1 of equal value as can be known.In addition, in Fig. 3, R1=1k Ω.When resistance R 1 is made as too small value, even if the resistance of the filament FL1 then during regular event, preheating is with also producing the direct voltage composition among the electric capacity C4.To this, comparatively it is desirable to, when the thermal resistance of filament FL1 is made as Rh, make R1＞10 * Rh during R1＞Rh, and actual use at least.
Fig. 4 represents the circuit diagram of employed testing circuit 11 and comparator 13 in the lighting apparatus for discharge lamp shown in Figure 1.Testing circuit 11 comprises resistance R 41 and capacitor C 41, and preheating is carried out smoothing with the voltage of electric capacity C4.Comparator 13 comprises photoelectrical coupler (Photocoupler) PC1, reaches voltage stabilizing didoe (Zener diode, Zener diode) ZD1.The anode of voltage stabilizing didoe ZD1 is connected in photoelectrical coupler PC1, and negative electrode is connected in capacitor C 41.The primary side of photoelectrical coupler PC1 is connected in voltage stabilizing didoe ZD1, and primary side is connected in control circuit 15.
When the direct voltage of capacitor C 41 surpasses the voltage of voltage stabilizing didoe ZD1, voltage stabilizing didoe ZD1 conducting, photoelectrical coupler PC1 conducting.So, control circuit 15 protection change-over circuit I1.
Like this, lighting apparatus for discharge lamp according to present embodiment, series circuit and filament FL1, the FL2 of diode D1, D2 and resistance R 1, R2 are connected in parallel, preheating detects the direct voltage composition with electric capacity C4, C5, therefore need not in primary side DC power supply portion be set in addition, just can detect the broken string of filament FL1, FL2 with simple structure.
And, make direct current flow to the resistance of filament because of not needing being used to like that shown in patent documentation 2 from DC power supply portion, thus component number can be cut down, and can detect the broken string of filament safely.
In addition, in Fig. 1, the capacitor C 3 of blocking usefulness via direct current is connected in the secondary coil T12 of insulating transformer T1 with preheating transformer T2, but also secondary coil T22-1, the T22-2 of preheating transformer T2 can be arranged on the primary side of insulating transformer T1.Perhaps, also can preheating transformer T2 be connected between source electrode (source)-drain electrode (drain) of switch element Q2 via the capacitor C 3 that direct current blocks usefulness.In addition, in Fig. 1, switch element Q1, Q2 double as are the switch element of filament preheating circuit and the switch element of change-over circuit I1, but the present invention is not limited thereto.That is, also the switch element that filament preheating circuit is used can be set in addition, control circuit 15 is controlled this switch element independently with change-over circuit I1.And, also can omit resonant circuit I2 among Fig. 1.In addition, their variation is also applicable among each following embodiment.
(embodiment 2)
Fig. 5 represents the circuit diagram of the lighting apparatus for discharge lamp of embodiments of the invention 2.Being characterized as of present embodiment: in order to detect the direct voltage composition of preheating, the direct voltage composition of terminal B, D when detection is benchmark with the accurate current potential G2 of secondary side group with electric capacity C4, C5.
Be connected with the testing circuit 11b of detection at terminal B at the direct voltage composition of primary side reference potential G2.And, be connected with the testing circuit 12d of detection at terminal D at the direct voltage composition of primary side reference potential G2.
The input impedance of testing circuit 11b, 12d (input impedance) is set to the value of the resistance of equal value that is higher than filament FL1, FL2.
Action specification during＜filament FL2 broken string 〉
When filament FL2 did not break, the resistance of equal value of filament FL2 was enough little.And, be connected with diode D2 and resistance R 2 on the filament FL2.Therefore, by the direct voltage composition that series circuit produced of diode D2 and resistance R 2, most of can consumption by filament FL2, the direct voltage composition of the terminal D of filament FL2 is roughly 0.Its result, the output of testing circuit 12d also is roughly 0.
When the resistance of equal value of filament FL2 broken string, filament FL2 increases, because of being connected with diode D2 and resistance R 2, so filament FL2 can not run out of the direct voltage composition that DC circuit produced by diode D2 and resistance R 2.Therefore, direct voltage becomes branch to be charged to preheating electric capacity C5, produces the direct voltage composition at terminal D.The voltage detected circuit 12d smoothing of terminal D, its direct voltage composition is input to comparator 14.
Action specification during＜filament FL1 broken string 〉
When filament FL1 does not break, because of the resistance of equal value of filament FL1 is enough little, and be connected with diode D1 and resistance R 1, so by the direct voltage composition that series circuit produced of diode D1 and resistance R 1, most of can consumption by filament FL1.Therefore, the direct voltage composition of the terminal B of filament FL1 is roughly 0, and the output of testing circuit 11b also is roughly 0.
When the resistance of equal value of filament FL1 broken string, filament FL1 increases, because of being connected with diode D1 and resistance R 1, so filament FL1 can not run out of the direct voltage composition that series circuit produced by diode D1 and resistance R 1.Therefore, direct voltage becomes branch to be charged to preheating electric capacity C4, produces the direct voltage composition among the terminal B.Testing circuit 11b is the voltage smoothing of terminal B, and exports its direct voltage composition to comparator 13.Comparator 13 is judged as filament and breaks when the output of testing circuit 11b surpasses reference voltage, and to control circuit 15 output abnormality decision signals.Control circuit 15 changes so that lighting apparatus for discharge lamp can not be in limit risk the frequency of oscillation of drive signal when being transfused to the abnormality juding signal, and the vibration of drive signal is stopped, thus protection change-over circuit I1.
As shown above, according to the lighting apparatus for discharge lamp of embodiment 2, even if utilizing preheating transformer T2 to make under the situation about insulating between power supply and the load, also can detect the broken string of filament FL1, FL2, protection change-over circuit I1 can improve fail safe.
And when the end of lifetime at discharge lamp FL, any emitter (emitter) among filament FL1, the FL2 consumes and when rectified action occurring in discharge lamp FL, can produce direct voltage composition about equally among terminal A, the B.This direct voltage composition is detected by testing circuit 11b.At this moment, constitute comparator 13 by the window comparator that comprises two reference voltages (windowcomparator).And; comparator 13; if the direct voltage composition of terminal B is in the scope of two reference voltages; then be judged as discharge lamp FL and do not reach end of lifetime; and when the direct voltage composition of terminal B exceeds the scope of two reference voltages; then be judged as discharge lamp FL and be in end of lifetime, and to control circuit 15 output abnormality decision signals, protection change-over circuit I1.Thus, also can carry out the protection of the end of lifetime of discharge lamp FL.
When discharge lamp FL did not reach end of lifetime, the secondary coil T22-1 of preheating transformer T2, T22-2 output AC square-wave voltage, direct voltage composition were 0 substantially.Therefore, filament FL1, FL2 are applied in alternating voltage.Under this state, the direct voltage composition of terminal A, B all is roughly 0, that is, the current potential of terminal A, B equates.
On the other hand, when discharge lamp FL reaches when rectified action occurring among end of lifetime, the discharge lamp FL, the both end voltage of discharge lamp FL (voltage between filament FL1 and the filament FL2) is positive and negative asymmetric.That is, the two ends of discharge lamp FL can produce the direct voltage composition.The polarity of this direct voltage composition has been consumed by which the emitter among filament FL1 and the filament FL2 and has determined.At this, because of terminal C ground connection, so can produce the direct voltage composition among terminal A, the B.Therefore, by constituting testing circuit 11b by window comparator,, also this situation can be detected, the life-span of discharge lamp FL can be detected reliably even if discharge lamp FL reaches end of lifetime and produce the direct voltage composition of plus or minus in terminal B.
Particularly, one of them reference voltage in two reference voltages of window comparator can be set at the value of the positive direct voltage composition that hypothesis produced in terminal B when discharge lamp FL reaches end of lifetime, the value that another reference voltage is set at the negative direct voltage composition that hypothesis produced when discharge lamp FL reaches end of lifetime in terminal B gets final product.
In addition, the polarity of the direct voltage composition that is occurred among the terminal B when filament FL1 breaks is determined by the polarity of diode D1.Therefore, one of them reference voltage in two of window comparator reference voltages is used for the judgement of the end of lifetime of the judgement of broken string of filament FL1 and discharge lamp FL.
Therefore, in Fig. 5, can't distinguish the detection of the broken string of the detection of end of lifetime of discharge lamp FL and filament FL1.To this, by the change in voltage of detection preheating usefulness electric capacity C4 in the foregoing description 1 or next embodiment 3, thereby no matter whether discharge lamp FL reaches end of lifetime, all can detect the broken string of filament FL1 reliably.
In addition, in Fig. 5, testing circuit 11b is connected in terminal B, but also can be connected in terminal A.
(embodiment 3)
The lighting apparatus for discharge lamp of embodiment 3 is a feature to adopt the structure that only can detect the broken string of filament in the detection of the end of lifetime of the burn out detection of filament and discharge lamp FL.Fig. 6 represents the testing circuit 11a in the lighting apparatus for discharge lamp of embodiments of the invention 3, the circuit diagram of 11b.At this, illustrate testing circuit 11a, and, also can adopt the testing circuit that has with testing circuit 11a same structure about filament FL2 at filament FL1.
In the circuit of Fig. 6, detect the direct voltage composition of terminal A, the B of filament FL1 respectively with testing circuit 11a, 11b, and with comparator 13 ' they are compared.And, in order easily to determine the broken string that has or not filament FL1, the overlapping direct voltage that the V1 of DC power supply portion is arranged on the detection voltage Va of the detected terminal A of testing circuit 11a.And, with detect voltage Va be made as comparator 13 ' reference voltage.And, the detection voltage of the detected terminal B of testing circuit 11b is made as Vb.
When not having the broken string of filament FL1, preheating is roughly 0 with the direct voltage composition of electric capacity C4.At this moment, terminal A exists hardly with the difference that the direct voltage of terminal B becomes to divide, and therefore passes through the bias voltage (bias) of the V1 of DC power supply portion, Va＞Vb.
When filament FL1 broke, preheating be with can producing the direct voltage composition among the electric capacity C4, and the polarity of diode D1 shown in Figure 6 is that the direct voltage composition of terminal B rises more than the direct voltage composition of terminal A.At this moment, set the circuit constant of testing circuit 11a, 11b, make Va＜Vb.Thus, when discharge lamp FL takes place when unusual, comparator 13 ' the output counter-rotating, therefore can make control circuit 15 protection change-over circuit I1.
On the other hand, when discharge lamp FL reach end of lifetime, when in discharge lamp FL, rectified action occurring, if filament FL1 does not break, then the direct voltage composition between terminal A, B is roughly 0, so Va＞Vb.Thus, do not detect the end of lifetime of discharge lamp FL.
Like this, according to the lighting apparatus for discharge lamp of present embodiment,, therefore can only detect the broken string of filament by the reference voltage of the V1 of DC power supply portion decision filament burn out detection.
In addition, in Fig. 6, when detecting the end of lifetime of discharge lamp FL, the window comparator of the output of one of them at least (window comparator) among input detecting circuit 11a and the 11b can be set in addition.And, when window comparator exceeds the scope of two reference voltages in the output of testing circuit 11a or testing circuit 11b, be judged as discharge lamp FL and reached end of lifetime, and to control circuit 15 output abnormality decision signals.Then, control circuit 15 allows change-over circuit I1 move to protection action to get final product.Thus, can protect discharge lamp FL at end of lifetime.
(embodiment 4)
Fig. 7 represents the circuit diagram of the lighting apparatus for discharge lamp of embodiments of the invention 4.Being characterized as of the lighting apparatus for discharge lamp of embodiment 4 is connected in series a plurality of discharge lamps.In addition, in the present embodiment, the part identical with embodiment 1 to 3 omitted explanation.Under the situation of Fig. 7, be connected in series with two discharge lamp FLa, FLb.Discharge lamp FLa comprises filament FLa1, FLa2.Filament FLa1 is connected between terminal A1 and the terminal B1.Filament FLa2 is connected between terminal C1 and the terminal E1.
Discharge lamp FLb comprises filament FLb1, FLb2.Filament FLb1 is connected between terminal A2 and the terminal B2.Filament FLb2 is connected between terminal C2 and the terminal E2.
Filament FLa2 is connected via terminal C1 and terminal A2 with filament FLb1.Terminal E1 is connected in terminal B2 via the series circuit of diode D3 and resistance R 3.
Preheating transformer T2 also possesses a secondary coil T22-3 except a pair of secondary coil T22-1, T22-2.The wherein end of secondary coil T22-3 is connected in terminal B2, and the other end is connected in terminal E1 via capacitor C 6.
Be connected in parallel to testing circuit 17 in capacitor C 6.Testing circuit 17 is in order to detect the broken string of filament FLa2, FLb1, exports the direct voltage composition of capacitor C 6 to comparator 18.
When filament FLa2, FLb1 broke, the polarity that charges to the direct voltage composition of capacitor C 6 was determined by the direction of diode D3.And even if any broken string among filament FLa2, the FLb1, capacitor C 6 also is recharged with identical polarity.Therefore, testing circuit 17 constitutes as long as consider the polarity of the direct voltage composition that charges to capacitor C 6, so the direction of diode D3 is not particularly limited.
Fig. 8 is the action specification figure of lighting apparatus for discharge lamp shown in Figure 7.Arrow among the figure is represented the direction of direct current.As filament FLa2, when FLb1 does not break, even if be recharged based on direct current capacitor C 6, the charging charge of capacitor C 6 can discharge via filament FLa2, FLb1 when the polarity inversion of secondary coil T22-3.Therefore, almost do not charged in the capacitor C 6 by the direct voltage composition.Thus, just often the direct voltage composition of capacitor C 6 is roughly 0.
Now, suppose filament FLa2 broken string.Like this, when being recharged based on direct current capacitor C 6, during the polarity inversion of secondary coil T22-3, the charging charge of capacitor C 6 can not be via filament FLa2 discharge, perhaps is difficult to discharge with just often comparing to become.
Its result produces the direct voltage composition in the capacitor C 6.By detecting the broken string that this direct voltage composition just can detect filament FLa2.
So, lighting apparatus for discharge lamp according to embodiment 4, can utilize a series circuit of diode D3 and resistance R 3, capacitor C 6, testing circuit 17 and comparator 18 to detect the broken string of two filament FLa2, FLb1, therefore need not increase the broken string that the parts number just can detect two filament FLa2, FLb1.
(liquid crystal indicator)
Fig. 9 represents the structure chart of the liquid crystal indicator of embodiments of the present invention.The back side of liquid crystal panel LCP (under) dispose BL backlight.BL backlight comprises basket 21, be arranged at the reflecting plate 22 of the top of basket 21, be disposed at the top of reflecting plate 22 discharge lamp 1 to 8, be arranged at the diffuser plate (diffuser plate) 23 of the top of discharge lamp 1 to 8 and be disposed at prismatic lens one or more optical sheets (opticalsheets) 24 such as (prism sheet) of the top of diffuser plate 23.
And, be provided with the lighting apparatus for discharge lamp 10 of lighting discharge lamp 1 to 8 at the back side of basket 21.As lighting apparatus for discharge lamp 10, can adopt any lighting apparatus for discharge lamp among the embodiment 1 to 4.Reflecting plate 22 makes the light of discharge lamp 1 to 8 point to the front.Diffuser plate 23 makes from the diffusion of the light of discharge lamp 1 to 8 and reflecting plate 22, and will be towards the Luminance Distribution equalization of the illumination light of front.
According to the liquid crystal indicator of present embodiment, in each pixel of liquid crystal panel LCP, drive liquid crystal according to image signal, from the light of BL radiation backlight by transmission, and on liquid crystal panel LCP display image.
In addition, also the lighting apparatus for discharge lamp shown in the embodiment 1 to 4 can be applicable to lighting device.In addition, the overall structure figure of lighting device is identical with the overall structure figure of the lighting apparatus for discharge lamp shown in the embodiment 1 to 4, therefore omits diagram.
(summary of the present invention)
(1) lighting apparatus for discharge lamp of the present invention is lighted the discharge lamp with filament, comprising: will be from direct current The output of source section is converted to high frequency output, and is supplied to the change-over circuit of described discharge lamp; Comprise for supplying with to described filament The pre-heat coil of preheat curent and the filament pre-heating that is connected in the preheating usefulness electric capacity between described pre-heat coil and the described filament Circuit; Comprise the rectifier cell and the resistance that are connected in series, and be connected in parallel in the series circuit of described filament; Detect described pre-The heat testing circuit of the DC voltage composition of electric capacity; The comparison that output and the reference voltage of described testing circuit compared Device; And the output that receives described comparator, limit the output of described change-over circuit or stop the action of described change-over circuit Control circuit.
According to this structure, be connected the series circuit of diode and resistance with filament parallel, preheating is pressed into the capacitance detecting direct current Divide, therefore need not in primary side dc source section be set in addition, just can detect the broken string of filament with simple structure.
And, make DC current flow to the electricity of filament from dc source section because not needing being used for like that shown in patent documentation 2 Resistance, thus component number can be cut down, and can detect safely the broken string of filament.
(2) and, in the said structure, comparatively it is desirable to, described testing circuit detects the direct voltage composition of voltage of at least one end of described filament.
According to this structure, the direct voltage composition of the voltage of at least one end by detecting filament can detect the broken string of filament.
(3) and, in the said structure, comparatively it is desirable to, described testing circuit comprises the 1st testing circuit of a wherein end that is connected in described filament and the 2nd testing circuit that is connected in the other end of described filament, described comparator as reference voltage, compares the detection voltage of one of them testing circuit in described the 1st testing circuit and the 2nd testing circuit to the detection voltage of described the 1st testing circuit and the 2nd testing circuit.
According to this structure, because detect respectively and the direct voltage composition of the voltage at the two ends of filament relatively, so can detect the broken string of filament or the bad connection of discharge lamp irrespectively, reliably with the rectified action of the end of lifetime of discharge lamp.
(4) comparatively it is desirable to, when the resistance value of establishing the resistance that is connected in series with described rectifier cell is the thermal resistance of R, described filament when being Rh, R＞Rh.
According to this structure, can increase poor that the direct voltage that occurred in electric capacity in the filament preheating when unusual just often becomes to divide, can improve the unusual accuracy of detection of filament.
(5) comparatively it is desirable to, described change-over circuit comprise with described DC power supply portion side as elementary, with described discharge lamp side as secondary transformer.
According to this structure, because of change-over circuit comprises transformer, so can light high-tension discharge lamp.Therefore, thin tube-like or microscler discharge lamp be can light, the large tracts of landization and the slimming of lighting device and liquid crystal indicator are easy to realize.
(6) comparatively it is desirable to described transformer is insulating transformer.
According to this structure,,, can prevent to get an electric shock so can make DC power supply portion and discharge lamp insulation because of change-over circuit comprises insulating transformer.
(7) lighting device of the present invention comprises each described lighting apparatus for discharge lamp in (1) to (6).
According to this structure, can provide the lighting device of each described lighting apparatus for discharge lamp in a kind of comprising (1) to (6).
(8) liquid crystal indicator of the present invention comprises each described lighting apparatus for discharge lamp in (1) to (6).
According to this structure, can provide the liquid crystal indicator of each described lighting apparatus for discharge lamp in a kind of comprising (1) to (6).
Claims (8)
1. a lighting apparatus for discharge lamp is lighted the discharge lamp with filament, it is characterized in that comprising:
Change-over circuit will be converted to high frequency output from the output of DC power supply portion, and be supplied to described discharge lamp;
Filament preheating circuit comprises and is used for supplying with the pre-heat coil of preheat curent and being connected in preheating electric capacity between described pre-heat coil and the described filament to described filament;
Series circuit comprises the rectifier cell and the resistance that are connected in series, and is connected in parallel in described filament;
Testing circuit detects the direct voltage composition of described preheating with electric capacity;
Comparator compares the output and the reference voltage of described testing circuit; And
Control circuit receives the output of described comparator, limits the output of described change-over circuit or stops the action of described change-over circuit.
2. lighting apparatus for discharge lamp according to claim 1 is characterized in that: described testing circuit detects the direct voltage composition of voltage of at least one end of described filament.
3. lighting apparatus for discharge lamp according to claim 1 is characterized in that,
Described testing circuit comprises the 1st testing circuit of a wherein end that is connected in described filament and the 2nd testing circuit that is connected in the other end of described filament;
Described comparator as reference voltage, compares the detection voltage of one of them testing circuit of described the 1st testing circuit and the 2nd testing circuit to the detection voltage of described the 1st testing circuit and the 2nd testing circuit.
4. according to each described lighting apparatus for discharge lamp in the claim 1 to 3, it is characterized in that: when the resistance value of establishing the resistance that is connected in series with described rectifier cell is the thermal resistance of R, described filament when being Rh, R＞Rh.
5. according to each described lighting apparatus for discharge lamp in the claim 1 to 4, it is characterized in that: described change-over circuit comprise with described DC power supply portion one side as elementary, with described discharge lamp one side as secondary transformer.
6. lighting apparatus for discharge lamp according to claim 5 is characterized in that: described transformer is an insulating transformer.
7. a lighting device is characterized in that comprising: as each described lighting apparatus for discharge lamp in the claim 1 to 6.
8. a liquid crystal indicator is characterized in that comprising: as each described lighting apparatus for discharge lamp in the claim 1 to 6.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2007162759 | 2007-06-20 | ||
| JP162759/2007 | 2007-06-20 | ||
| PCT/JP2008/060637 WO2008156015A1 (en) | 2007-06-20 | 2008-06-11 | Discharge lamp operating device, illumination device, and liquid crystal display device |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN101690409A true CN101690409A (en) | 2010-03-31 |
| CN101690409B CN101690409B (en) | 2012-11-21 |
Family
ID=40156172
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200880019381.0A Expired - Fee Related CN101690409B (en) | 2007-06-20 | 2008-06-11 | Discharge lamp operating device, illumination device, and liquid crystal display device |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US8129915B2 (en) |
| EP (1) | EP2160079A4 (en) |
| JP (1) | JP4807454B2 (en) |
| CN (1) | CN101690409B (en) |
| WO (1) | WO2008156015A1 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102595746A (en) * | 2011-01-12 | 2012-07-18 | 硕颉科技股份有限公司 | Driving device of fluorescent tube and method and lighting device thereof |
| CN102647840A (en) * | 2011-02-21 | 2012-08-22 | 松下电器产业株式会社 | Electric-discharge lamp lightening device and illumination device comprising same |
| CN103547050A (en) * | 2012-07-16 | 2014-01-29 | 台达电子工业股份有限公司 | Lighting up system and lighting up method |
| US8760084B2 (en) | 2011-01-04 | 2014-06-24 | Beyond Innovation Technology Co., Ltd. | Driving apparatus for fluorescent tube and method thereof and illumination apparatus using the same |
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| JP2009094044A (en) * | 2007-09-21 | 2009-04-30 | Panasonic Electric Works Co Ltd | Lighting device, back light unit, and liquid crystal display |
| WO2009154180A1 (en) * | 2008-06-20 | 2009-12-23 | パナソニック電工株式会社 | Illumination lighting device, illuminating device, and illuminating system |
| JP5493618B2 (en) * | 2009-09-14 | 2014-05-14 | セイコーエプソン株式会社 | Lighting device and projector |
| JP5892172B2 (en) | 2011-10-25 | 2016-03-23 | 株式会社村田製作所 | Inverter device |
| EP2810364B1 (en) * | 2012-02-01 | 2017-07-12 | Dialight Corporation | Independently adjustable current and voltage ac-ac converter |
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| JPS6386396A (en) * | 1986-09-30 | 1988-04-16 | 東芝ライテック株式会社 | Direct connection type discharge lamp lighter |
| US5449979A (en) * | 1992-09-25 | 1995-09-12 | Matsushita Electric Works, Ltd. | Inverter power supply |
| US5627434A (en) * | 1993-10-26 | 1997-05-06 | Canon Kabushiki Kaisha | Apparatus for operating a fluorescent lamp of an image forming apparatus |
| JP3858317B2 (en) * | 1996-11-29 | 2006-12-13 | 東芝ライテック株式会社 | Discharge lamp lighting device and lighting device |
| JPH10284275A (en) | 1997-04-02 | 1998-10-23 | Matsushita Electric Works Ltd | Discharge lamp lighting device |
| JPH1126184A (en) * | 1997-07-04 | 1999-01-29 | Canon Inc | Fluorescent lamp driving circuit and image forming device using this |
| JP2001015289A (en) * | 1999-04-28 | 2001-01-19 | Mitsubishi Electric Corp | Discharge lamp lighting device |
| TW458485U (en) * | 2000-07-31 | 2001-10-01 | Nat Science Council | Pre-heat circuit of gas discharging lamp |
| JP2002141184A (en) * | 2000-10-31 | 2002-05-17 | Matsushita Electric Works Ltd | Discharge lamp lighting device |
| JP3835534B2 (en) * | 2001-03-02 | 2006-10-18 | 東芝ライテック株式会社 | High-intensity discharge lamp lighting device and lighting device |
| JP2003036987A (en) * | 2001-07-24 | 2003-02-07 | Harison Toshiba Lighting Corp | Discharge lamp lighting device, equipment and image forming device |
| JP4460202B2 (en) * | 2001-12-28 | 2010-05-12 | パナソニック電工株式会社 | Discharge lamp lighting device |
| JP4144231B2 (en) * | 2002-02-25 | 2008-09-03 | 松下電工株式会社 | Discharge lamp lighting device |
| US7154232B2 (en) * | 2003-06-24 | 2006-12-26 | International Rectifier Corporation | Ballast control IC with multi-function feedback sense |
| EP1819205B1 (en) * | 2004-12-03 | 2011-10-05 | Panasonic Electric Works Co., Ltd. | Electric discharge lamp operation device and illumination instrument |
| JP4696688B2 (en) * | 2005-05-25 | 2011-06-08 | パナソニック電工株式会社 | Discharge lamp lighting device and lighting fixture |
| JP4735239B2 (en) * | 2005-12-22 | 2011-07-27 | パナソニック電工株式会社 | Discharge lamp lighting device and image display device |
| JP4631817B2 (en) * | 2006-06-27 | 2011-02-16 | パナソニック電工株式会社 | Discharge lamp lighting device and lighting fixture |
| JP4608470B2 (en) * | 2006-08-31 | 2011-01-12 | パナソニック電工株式会社 | Discharge lamp lighting device and lighting device |
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2008
- 2008-06-11 US US12/663,596 patent/US8129915B2/en not_active Expired - Fee Related
- 2008-06-11 JP JP2009520439A patent/JP4807454B2/en not_active Expired - Fee Related
- 2008-06-11 CN CN200880019381.0A patent/CN101690409B/en not_active Expired - Fee Related
- 2008-06-11 WO PCT/JP2008/060637 patent/WO2008156015A1/en active Application Filing
- 2008-06-11 EP EP08765416.6A patent/EP2160079A4/en not_active Withdrawn
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8760084B2 (en) | 2011-01-04 | 2014-06-24 | Beyond Innovation Technology Co., Ltd. | Driving apparatus for fluorescent tube and method thereof and illumination apparatus using the same |
| CN102595746A (en) * | 2011-01-12 | 2012-07-18 | 硕颉科技股份有限公司 | Driving device of fluorescent tube and method and lighting device thereof |
| CN102647840A (en) * | 2011-02-21 | 2012-08-22 | 松下电器产业株式会社 | Electric-discharge lamp lightening device and illumination device comprising same |
| CN103547050A (en) * | 2012-07-16 | 2014-01-29 | 台达电子工业股份有限公司 | Lighting up system and lighting up method |
| CN103547050B (en) * | 2012-07-16 | 2015-11-25 | 台达电子工业股份有限公司 | Lighting system and ignition method |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2008156015A1 (en) | 2008-12-24 |
| CN101690409B (en) | 2012-11-21 |
| JP4807454B2 (en) | 2011-11-02 |
| US8129915B2 (en) | 2012-03-06 |
| EP2160079A1 (en) | 2010-03-03 |
| US20100176739A1 (en) | 2010-07-15 |
| EP2160079A4 (en) | 2014-03-19 |
| JPWO2008156015A1 (en) | 2010-08-26 |
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